NOTES.md

2026-05-05 — Fix validate ADC anchors and restore rf_shape_tuples

• get_tr_waveforms failed on multi-block repeated segments (e.g., mprage) because segment lookup used find_segment_for_block_pos(n) against segment.start_block (first-occurrence only), causing missing anchors on later occurrences.
• Correct fix in pulseqlib_waveforms.c: use scan_table_seg_id[block_idx] only when block_order == NULL (degenerate/single-pass path where block_idx maps to scan-table position).
• For ADC anchor blk_in_seg, use precomputed occurrence offsets (scan_blk_in_occ) only when block_order == NULL; keep fallback n - seg->start_block for non-degenerate average-expanded passes.
• Gotcha: in non-degenerate average-expanded passes, block_order[n] is a block-table index, not a scan-table position; indexing scan_table_seg_id with it breaks anchor lookup (seen in bssfp navg=3).
• _get_sequence_description now emits rf_shape_tuples by scanning segment blocks per unique RF, retrieving stats via pulseqlib_get_rf_stats, and waveform arrays via pulseqlib_get_rf_magnitude/phase/time_us.
• Wrapper implementation uses pulseqlib_internal.h for read-only descriptor access (rf_definitions, segment_definitions) and frees all C-allocated RF arrays with PULSEQLIB_FREE.